Ecology is studied at very large scales: Biosphere


















What makes up the BIOSPHERE?

Energy and water exist and move around the biosphere in different forms

Where does energy come from?



















“A thing is right when it tends to preserve the integrity, stability, and beauty of the biotic community. It is wrong when it tends otherwise” -Aldo Leopold

Painting Chalon Sombrero


Albedo


Global albedo is highly variable


Albedo feedbacks and Snowball Earth


Earth’s average albedo is ~0.3, keeping surface @ 15°C

Do you think albedo is changing?

Albedo: cold generates cold but…..

Sun is the Earth’s primary form of heat energy, via radiation




  • ~1/3 of sunlight energy reflects back to space


  • Rest is absorbed by land, ocean and atmosphere


  • Exact amount absorbed depends on both surface and atmosphere




  • The balance of incoming and outgoing radiation makes up Earth Energy Budget

Why clouds are cool…



Atmospheric absorption spectra



Composition of the atmosphere




  • Gases have different RESIDENCE TIMES
    • N2 = 13 million years
    • O2 = 10,000 years
    • N20 = 114 years
    • CH4 (methane) = 12 years
    • CO2 = 5-200 years (1/2 removed quickly)



  • Water vapor is reactive and highly variable
    • 10 day residence time
    • seasonally and spatially

Changes in composition impact atmospheric heating


Water vapor is the most abundant greenhouse gas







  • NASA recently confirmed heat-trapping effect of water in the air
    • critical component of global change
    • collects at tropical latitudes


  • 2x climate warming caused by increased CO2

Solar energy & water cycle connected


Water cycle = continuous movement of water within the earth and atmosphere




















25% of incoming solar energy leaves the surface through evaporation

Evapotranspiration: Energetics of water movement





  • Water has high specific heat
    • 4x more energy to heat water than air
    • uses up solar energy


  • 30% of oceans evaporate per year
  • >60% of rainfall is lost to evapotranspiration


  • Large energy fluxes when water changes state
    • evapotranspiration cools surfaces
    • condensation warms atmosphere

Global water cycle: 577,000 km3 of water circulates each year


Global water cycle: Residence times matter


Water for humans?